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2011-01-18

Quantum Entanglement Allows Time Teleportation

New Type Of Entanglement Allows 'Teleportation in Time,' Say Physicists

Conventional entanglement links particles across space. Now physicists say a similar effect links particles through time.

To see how, imagine an experiment that Ralph and Olson describe in which a qubit is sent into the future. The idea is that a detector acts on a qubit and then generates a classical message describing how this particle can be detected. Then, at some point in the future, another detector at the same position in space, receives this message and carries out the required measurement, thereby reconstructing the qubit.

But there's a twist. Olson and Ralph show that the detection of the qubit in the future must be symmetric in time with its creation in the past. "If the past detector was active at a quarter to 12:00, then the future detector must wait to become active at precisely a quarter past 12:00 in order to achieve entanglement," they say. For that reason, they call this process "teleportation in time".

Time travel is the concept of moving between different points in time in a manner analogous to moving between different points in space, either sending objects (or in some cases just information) backwards in time to some moment before the present, or sending objects forward from the present to the future without the need to experience the intervening period (at least not at the normal rate).

Quantum entanglement is a property of the quantum mechanical state of a system containing two or more objects, where the objects that make up the system are linked in such a way that the quantum state of any member of the system cannot be adequately described without full mention of the other members of the system, even if the individual objects are spatially separated. Quantum entanglement is at the heart of the EPR paradox that was described by Albert Einstein, Boris Podolsky, and Nathan Rosen in 1935, and it was experimentally verified for the first time in 1972 by Stuart Freedman and John Clauser[1].

Quantum teleportation, or entanglement-assisted teleportation, is a technique used to transfer quantum information from one quantum system to another. It does not transport the system itself, nor does it allow communication of information at superluminal (faster than light) speed. Neither does it concern rearranging the particles of a macroscopic object to copy the form of another object. Its distinguishing feature is that it can transmit the information present in a quantum superposition, useful for quantum communication and computation.